we already launched a vehicle recommendation engine (https://driverbase.com/recommendation/step1) and a marketplace that is now almost up to 1 million vehicle listings without webscraping (https://driverbase.com/inventory).
this sell my car feature is new... we just launched it last week and it is definitely a work in progress: https://driverbase.com/company/update-v5681/
as you can see in this thread we take user feedback very seriously and have been actively making improvements.